SuperWASP Processing

The SuperWASP consortium provided the FITS files from the first WASP data release. SuperWASP calculates raw and SYSREM corrected fluxes in units of micro-Vegas, designated FLUX2 and TAMFLUX2 respectively. There are no FLUX1 and TAMFLUX21 values, and the numbering is an artifact of the WASP processing pipeline. SuperWASP also provides the observation times in units of seconds transpired since a Julian reference date. The NASA Exoplanet Archive generated IPAC ASCII table (.tbl) files from the FITS files and added the observation times in HJD, the fluxes in units of apparent magnitudes, for both the raw and SYSREM corrected fluxes, along with associated errors.

The archive uses the following time conversion formula:

Time in HJD (days) = HJD reference time + (time in seconds since HJD reference time)/86400.0

To convert the micro-Vega fluxes, both for the FLUX2 and TAMFLUX2 columns, we use the formula:

apparent magnitude (MAG2 or TAMMAG2) in the WASP bandpass = 15.0 - (2.5 * log10(FLUX2 or TAMFLUX2 respectively))

and for the associated magnitude errors:

apparent magnitude error for MAG2_ERR or TAMMAG2_ERR = 1.08574 * FLUX2_ERR/FLUX2 or TAMFLUX2_ERR/TAMFLUX2 respectively

Magnitude Time Series Statistics Calculations

As part of the NASA Exoplanet Archive service, a standard set of time series statistics are performed on the TAMMAG2 magnitude time series, described above. These include the calculation of the mean, median, standard deviations and 5-95 percentile range, and the results are included in the SuperWASP metadata served here.

NOTE: All statistics for time series with only one data point that actually made it into the statistics calculation are null. This affects on order 1% of the data set, or 180,000 records. Of these, 95% have only one data point in the time series. The remainder are filtered down to one data point in the statistics calculation.

Errors During Processing

In the preparation of the IPAC ASCII tbl files, we identified a small number of files with data processing errors. In particular, the following three targets have empty metadata records and their TAMFLUX2 column has been populated with zeros. These files are not included in the archive:

Data Release Tile Target
DR1 tile144048 1SWASP J094756.49-400004.7
DR1 tile090066 1SWASP J061431.16-221005.9
DR1 tile144060 1SWASP J095451.03-254440.5

The following two targets had corrupted FITS files and are not included in the archive:

Data Release Tile Target
DR1 tile144108 1SWASP J093643.60+235119.0
DR1 tile144102 1SWASP J094926.39+144023.2

Last updated: 10 December 2013